Just to support what Xenon and Kaishang have said.
I had a non fault accident just under 3 years ago. There was a little bit of damage to my bumper and the other drivers headlight was broken. The other guy wanted to claim his insurance due to being an idiot so we both had to report the incident to our insurers. It only cost £120 to get my bumper fixed so no way was I going to claim and pay a massive excess. I made certain that my insurance company were aware of this. I asked if my premium would be affected even though I wasn't making a claim and I was informed that it wouldn't.
The next year when it was renewal time I received a ridiculous renewal quote from Admiral. I therefor decided to change insurer and found a much cheaper quote from Elephant (didn't realise they were the same company at that time). When I called Admiral they pointed out that they were the same company and the reason Elephant had been so cheap was because I hadn't listed the accident. When this was listed the price nearly doubled.
Like I said, insurance is now a last resort for me. I agree that car insurance in this country is a joke.